Many studies have been heretofore made on the method of obtaining an oxygen-containing compound from an olefin and oxygen.
In particular, with respect to the catalyst of producing acetic acid from ethylene and oxygen through one stage, for example, a liquid phase one-stage oxidation process using an oxidation-reduction catalyst comprising a metal ion pair such as palladium-cobalt and palladium-iron (see, Patent Document 1 (French Patent No. 1,448,361)), a process using a catalyst comprising a palladium-phosphoric acid or a sulfur-containing modifying agent (Patent Document 2 (Japanese Unexamined Patent Publication (Kokai) No. 47-013221) and Patent Document 3 (Kokai No. 51-029425)), and a gas phase one-stage oxidation process using a catalyst comprising a 3 group-type oxygen compound (see, Patent Document 4 (Kokoku No. 46-006763)) have been proposed.
Also, with respect to the process of producing acetic acid by using a catalyst containing a palladium compound and a heteropolyacid, for example, a gas phase one-stage oxidation process using a catalyst comprising palladium phosphovanadomolybdate has been proposed (see, Patent Document 5 (Kokai No. 54-57488)).
Further, a catalyst containing at least one compound selected from the group consisting of palladium, heteropolyacids and salts thereof is disclosed as a catalyst of ensuring higher productivity and selectivity than those of the above-described various catalysts (see, Patent Document 6 (Kokai No. 7-89896) and Patent Document 7 (Kokai No. 9-67298)).
These catalysts comprising palladium and a heteropolyacid have a sufficiently high performance in industrially producing acetic acid from ethylene and oxygen. However, the heteropolyacid is low in the thermal stability, specifically, unstable at a temperature of 400° C. or more, and therefore, requires care in view of stable operation. In addition, it is difficult to perform firing at a high temperature for the reclamation of catalyst.
On the other hand, a composite oxide catalyst has been reported as a catalyst of producing acetic acid from ethylene and oxygen. This composite oxide is characterized by having relatively high heat resistance as compared with heteropolyacids.
EP-A-294,845 (Patent Document 8) discloses a process for selectively producing acetic acid from ethane, ethylene or a mixture thereof and oxygen in the presence of a catalyst mixture containing:
A) a calcined catalyst represented by the formula:MoxVy or MoxVyYz [wherein Y can be one or more metals of Li, Na, Be, Mg, Ca, Sr, Ba, Zn, Cd, Hg, Sc, Y, La, Ce, Al, Ti, Lr, Hf, Pb, N b, Ta, As, Sb, Bi, Cr, W, U, Te, Fe, Co and Ni, x is 0.5 to 0.9, y is 0.1 to 0.4, and z is 0.001 to 1], and
B) an ethylene hydration catalyst and/or an ethylene oxidation catalyst. The second catalyst component B is suitably a molecular sieve catalyst or a palladium-containing catalyst, and high performance cannot be obtained by a catalyst containing the component A or B alone.
EP-A-407,091 (Patent Document 9) discloses a process for producing a mixture comprising ethylene and/or acetic acid. In this case, a gas containing ethane and/or ethylene and molecular oxygen is brought into contact with a catalyst composition containing elements A, X and Y at a high temperature, where A is ModReeWf (wherein d and f each is 0 or more, e is more than 0, and d+e+f=1), X is Cr, Mn, Nb, Ta, Ti, V and/or W, and Y is Bi, Ce, Co, Cu, Fe, K, Mg, Ni, P, Pb, Sb, Si, Sn, Tl and/or U.
International Publication No. 99/20592 (Patent Document 10), pamphlet, discloses a process of selectively producing acetic acid in a high temperature region from ethane, ethylene or a mixture thereof and oxygen in the presence of a catalyst represented by the formula:MoaPdbXcYd [wherein X represents one or multiple members of Cr, Mn, Nb, Ta, Ti, V, Te and W; Y represents one or multiple members of B, Al, Ga, In, Pt, Zn, Cd, Bi, Ce, Co, Rh, Ir, Cu, Ag, Au, Fe, Ru, Os, K, Rb, Cs, Mg, Ca, Sr, Ba, Nb, Zr, Hf, Ni, P, Pb, Sb, Si, Sn, Tl and U; a=1, b=0.0001 to 0.01, c=0.4 to 1, and d=0.005 to 1].
International Publication No. 00/00284, pamphlet (Patent Document 11) discloses MoVNbPd or MoVLaPd as the catalyst for obtaining acetic acid from ethylene and oxygen.
With respect to the catalyst containing tungsten and noble metal, International Publication No. 98/47850 (Patent Document 12), pamphlet, discloses a production process of acetic acid from ethane, ethylene or a mixture thereof, and also discloses a catalyst represented by the formula:WaXbYcZd [wherein X represents one or multiple members of Pd, Pt, Ag and Au, Y represents one or multiple members of V, Nb, Cr, Mn, Fe, Sn, Sb, Cu, Zn, U, Ni and Bi, Z represents one or multiple members of Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, Ba, Sc, Y, La, Ti, Zr, Hf, Ru, Os, Co, Rh, Ir, B, Al, Ga, In, Tl, Si, Ge, Pb, P, As and Te, a=1, b>0, c>0 and d=0 to 2]. But, this patent publication is silent on the reactivity when ethylene is used as the raw material, and moreover, sufficiently high performance is not obtained.
In this International Publication No. 98/47850 (Patent Document 12), pamphlet, it is stated that since the catalyst containing molybdenum disadvantageously produces a volatile molybdenum compound under the reaction conditions and the compound produced decreases the activity of catalyst and the selectivity, a catalyst system mainly comprising more stable tungsten is proposed.
However, International Publication No. 98/47850 (Patent Document 12), pamphlet, sets forth no working example using ethylene as a raw material. This catalyst system is presumed to have high oxidation activity so as to activate ethane low in the reactivity and therefore, when a large amount of ethylene having high reactivity is introduced, there may arise an overreaction such as polymerization or combustion reaction of ethylene. In any case, the catalyst described in this patent publication cannot be understood as an optimal catalyst system in the case of using ethylene as a raw material.
[Patent Document 1] French Patent 1,448,361
[Patent Document 2] Kokai No. 47-013221
[Patent Document 3] Kokai No. 51-029425
[Patent Document 4] Kokoku No. 46-006763
[Patent Document 5] Kokai No. 54-57488
[Patent Document 6] Kokai No. 7-89896
[Patent Document 7] Kokai No. 9-67298
[Patent Document 8] EP-A-294,845
[Patent Document 9] EP-A-407,091
[Patent Document 10] International Publication No. 99/20592, pamphlet
[Patent Document 11] International Publication No. 00/00284, pamphlet
[Patent Document 12] International Publication No. 98/47850, pamphlet